A Guide to Windows

Home Efficiency
May 25, 2017

You may not realize it, but your home’s windows play a very important role in your life. The best windows provide natural lighting, increase air flow, and make your house look great from the inside out. Windows also play a big role in your home’s efficiency. Modern windows offer better insulation, which makes it easier for your heating and cooling system to keep your home cozy.

Like every part of your house, windows require upkeep. However, in an aging house, maintenance isn’t always the answer, and getting the most out of your windows could mean replacing them completely. But how do you know if your windows need replacing?

Asking yourself a few important questions may help guide you in the direction:

  • Does it take superhuman strength to open your windows?
  • Do you feel cold breezes when standing near your windows in the winter?
  • Do your frames look worn out and rotten?

If you answered yes to any of these, it might be time to ditch those old windows and invest in new ones.

Choosing new windows can seem like a stressful undertaking, so it’s important to take your time and do your research. Navigating the world of energy efficient windows isn’t always easy, but knowing what to expect can make the process a whole lot smoother—that’s what we’re here for.

This guide breaks down the basics to help make your window replacement process that much easier. Learn about window types, frames, coatings, films, and more. With these tips and guidelines, you’ll be poised to make a smart investment in energy efficient windows.

Guide to windows - Framing

Framing Your Windows

As you begin shopping for energy efficient windows, look at frame styles first. A window frame provides support, holding the main parts of your window in place. Quality frames help keep your home insulated, and ensure the window’s glass pane is held sturdy—plus, they can add some serious style to your home’s exterior.

Window frames come in a wide variety of materials. The most common options are wood, vinyl, fiberglass, and aluminum. Each comes with its own set of benefits. Not sure which one you need? Don’t worry, we have you covered.

  • Wood Frames: Homeowners with older homes often prefer wood window frames, and it’s easy to see why. The beautiful, natural grain in wooden frames makes for a great complement to vintage design. Keep in mind that wooden frames need a lot of maintenance. You’ll have to periodically paint or stain your frames, and treat them regularly to protect against moisture and rot. Wooden frames tend to be on the more expensive end of the spectrum.

  • Vinyl Frames: Vinyl frames are one of the most popular framing options for modern homeowners. They’re made of PVC and provide excellent insulation. These frames do have their drawbacks, as vinyl isn’t as durable as wood or fiberglass. Some homeowners feel that vinyl windows don’t offer much charm, so if you’re focused on a welcoming appearance, vinyl might not be the right choice for you.

  • Fiberglass Frames: These types of frames are less common, but they do offer some great benefits. Fiberglass is durable and it can give your home an extra boost of insulation. Similar to vinyl, fiberglass frames aren’t always the most attractive, and they tend to be more expensive than other framing options.

  • Aluminum Frames: If you’re looking for durable, long-lasting window frames, aluminum could be the winner. With a sleek, clean look, these frames complement modern home design well. Aluminum frames don’t have as many maintenance issues, meaning you can enjoy the benefits of new windows without the hassle of dealing with rot or other common problems. Unfortunately, aluminum windows generally aren’t great energy savers, and they may come up short when compared to other more energy efficient window options.

Should I Replace or Repair My Window Frames?

It can be tough to choose between replacing and repairing your window frames, and knowing the difference will make you the knowledgeable homeowner your friends envy. In some cases, it may be easier to repair, but it’s important to look at the reasons your frame is no longer effective. This is especially true in the case of wooden frames; while a crack may be easy to seal up, rot and moisture damage may be a lost cause.

No matter what type of frame your windows have, you should consider overall condition of your window before repairing the frame. If your windows are older and made with a single pane of glass, they’ll likely feel drafty. These drafts can result in heat loss in the winter, and see your home losing cool air in the summer. This makes your heating and cooling system work double-time to keep you cozy, which means a big spike in your energy bill.

In these cases, when both frame and windowpane need to be upgraded, you may find a complete replacement is a better use of your time and money.

Guide to windows - Window Styles

Window Styles

You have plenty of window styles to choose from. Take a look at some of the most popular window style options for your home, and decide which best suits your design scheme and energy efficiency needs.

  • Double-Hung Windows: Double-hung windows feature two sashes, which are — the movable panels inside window frames that holds the glass panes and framework together. These two sashes are designed to slide up and down within the frame. Double-hung windows offer a classic look that matches common home styles well. You can open them from the bottom or the top, but the windows remain inside the frame and won’t jut out from your home. The average cost of a double hung window ranges from $300 to $850.

    Pros: These are some of the most energy efficient window options on the market, and you can save a lot on heating and cooling costs with this window style. Because you can open the bottom and top of the window at the same time, it’s easier to ventilate your home. Double-hung windows are generally low maintenance, so if you’re looking for a hands-off investment, these are a safe bet.

    Cons: These windows tend to be more expensive than single-hung styles.

  • Bay Windows: If you want to add beauty and elegance to your home, bay windows might be the answer. This window style helps open up the appearance of space, letting you make the most of the view outside your home. These windows jut outward from the main walls of a house, forming a bay within the room that looks great both outside and inside. The average cost of a bay window ranges from $1,150 to $3,550.

    Pros: Bay windows provide fantastic views and can make a small space look and feel larger. Thanks to their size and design, bay windows let in more natural light, and look great in homes of all sizes and design.

    Cons: Because bay windows allow in a great deal of natural light, they can also let in a significant amount of natural heat. If you’re shopping for bay windows, be sure to look for energy efficient windows that deflect the sun’s rays without sacrificing the light they provide.

  • Slider Windows: Slider windows feature panes that glide along a track. Generally these have at least one window that moves horizontally over another window. You’ll often find slider windows in contemporary homes, as these are a popular modern option. The average cost of a slider window ranges from $320 to $1,300.

    Pros: Slider windows can help make a room seem taller and are a good option for homes with shorter walls. They’re simple to maintain and easy to clean. Depending on design, they may help improve ventilation.

    Cons: Slider windows aren’t very energy efficient, because it’s harder to create a tight seal with this window style.

  • Awning Windows: You can open awning windows outward, letting air flow in from the bottom, left, or right. In general, awning windows can be installed next to, above, and below your traditional stationary windows. The average cost of an awning window ranges from $420 to $760.

    Pros: Awning windows provide great views, and because they’re made of a single piece of glass, may also offer better insulation, making them an energy efficient window option.

    Cons: Awning windows can be unsafe, as they’re harder to escape from in the case of an emergency. Awning windows also need more maintenance because they’re more easily hit by rain and other stormy weather conditions. If you choose this style of window, be prepared to clean it more often.

  • Casement Windows: Casement windows are operated with a crank, and can open outward to the right or left depending on how you get them installed. They usually have a vertical single sash. The average cost of a casement window ranges from $270 to $750.

    Pros: These side-opening windows offer great ventilation and high-quality insulation. They’re also easy to maintain and clean.

    Cons: Casement windows can age quickly, and offer less security than other window types. When it comes to opening casement windows, you’ll often deal with two extremes: the window is either closed or completely open because it can be difficult to adjust.

  • Transom Windows: Transoms are accent windows that can be rectangular, angled, or fan-shaped. They’re usually installed either directly above or below another window or door. The average cost of a transom window ranges from $200 to $575.

    Pros: These picture perfect windows can do wonders for curb appeal, and add extra light wherever they’re installed. With the right design, transoms can also improve ventilation.

    Cons: Some homeowners find that these decorative windows can be a bit hard to clean, meaning you’ll spend more time on upkeep.

Window Ratings

When shopping for energy efficient windows, you’ll see a variety of energy ratings systems and labels. Knowing which ratings to look for can help you narrow down your choices.

  • U-Value/U-Factor: U-Value, sometimes called U-Factor, measures the rate of heat transfer—it tells you how much heat is lost or gained through your window. The U-Value of a window can range from .20 to 1.20. The lower the U-Value, the more energy efficient your window is bound to be.

  • DP: Design Pressure tells you how much pressure a window can take before breaking. This measurement can range from 15 to 50. The higher the rating, the stronger the window.

  • SHGC: The Solar Heat Gain Coefficient measures the amount of solar radiation and heat that your windows allow inside the home. The lower the number, the less radiation. This measurement can range from 0 to 1.

  • Air Leakage: This measures the amount of air that a window allows to pass through. The lower the number, the more airtight the window. Air leakage doesn’t have a certain range, but 0.3 is the standard building code.

  • Visible Transmittance: Visible Transmittance tells you how much light is allowed to pass through a window. It’s measured on a scale from 0 to 1; the lower the number, the dimmer the room.

  • Condensation Resistance: This measures how much moisture is able to build up on the surface of your window. It’s measured on a scale from 1 to 100; the lower the number, the more condensation, which can lead to more window damage.

Certification Labels

Certification labels are important. You’ll run into these labels when window shopping, and it’s important to understand how they’re awarded.

  • NFRC Certification Label: The National Fenestration Rating Council (NFRC) helps consumers compare window performance through various ratings, including U-Factor, Solar Heat Gain Coefficient, Air Leakage, Visible Transmittance and Condensation Resistance.

  • ENERY STAR Certification Label: ENERY STAR qualification is based only on U-factor and SHGC ratings only. This certification itself doesn’t measure anything. It uses NFRC’s overall window thermal test results to create zones for particular areas in the country; it then recommends U-factor and SHGC values for these areas.

  • NAMI Structural Certification Label: The National Accreditation and Management Institute (NAMI) is an independent company that inspects and certifies windows, doors, and other products. It provides energy performance ratings based on values including U-Factor and SHGC.

  • American Architectural Manufacturers Association (AAMA) Certification label: This certification requires three tests: Water Leakage, Structural Strength, and Air Leakage.

We want to make sure you get the most out of your energy efficient windows, so we’ve set some parameters for window replacements to keep it simple.

In order to receive financing through Renovate America, energy efficient windows must be NFRC Certified, feature a U-Factor rating equal to or less than 0.30, and a SHGC rating equal to or less than 0.25.

With these impressive energy efficient ratings on your side, your investment in new windows is sure to provide great returns.

Window Films and Coatings

There are many types of treatments that can make your window function better. Learning about the various films and coatings used for energy efficient windows can help you make a better investment.

  • Decorative Window Film: This window film is very thin, and generally used only for decoration. It can help make your window’s glass panes look better, and enhance your privacy while reducing glare.

  • Solar Control Film: If you’re on the hunt for energy efficient windows, look for solar control film, also called Low-E or Low-emissivity film. This is a cost effective way to protect the interior of your home while enhancing energy efficiency.

    These coatings help control heat transfer with insulated glazing—meaning the sun won’t heat up your living space. Though energy efficient windows crafted with low-e coatings are about 10 to 15 percent more expensive than traditional windows, they can reduce energy loss by up to 50 percent.

  • Window Security Film: This type of film helps prevent excess damage if your window ruptures. If your window ever breaks, the film prevents harmful shards from falling and hurting people by keeping the pieces of glass stuck to the coating.

  • Storm Security Film: If your house gets hit with heavy storms and rough weather, you may want to invest in storm security film. This treatment makes your windows more durable and prevents dangerous shards from flying everywhere if your windows break.

  • Reflective Coatings: This type of coating helps reduce the transmission of solar radiation, helping to block more light than heat. These coatings reduce VT and SGHC values, and come in a variety of colors.

Guide to windows - Installation


Installing your energy efficient windows correctly is crucial. DIY window replacement tips don’t often account for the various problems and issues that arise during a window renovation. If a window is installed improperly, your window’s performance will suffer. It’s important to hire a skilled installer to complete the job.

Financing New Windows

It’s important to examine the numbers behind window replacements. Understanding the investment costs and potential energy savings can help you decide choose the right window upgrade.

The cost of windows varies by type and size, but there are certain costs that tend to remain consistent, especially when it comes to installment. In 2017, the average cost of window installation fell between $2,602 and $7,404. In general, the more windows installed, the more extensive the cost.

Most homeowners find they must spend between 1 and 2 percent of the purchase price of their home each year for routine maintenance projects, and window replacement is often a large portion of those expenses.

What do the savings look like? Energy Star reports that homeowners can expect to save up to hundreds of dollars after replacing windows. The typical home can save $16 to $465 annually when replacing single pane windows with modern double-pane windows.

Window Maintenance

While modern, energy efficient windows don’t require a great deal of maintenance, proper care is a key part of any home upgrade. If you want your windows to last longer and work better, it’s important to follow a few simple maintenance practices.

Replacing your windows is a big investment; make sure you do what you can to extend the lifespan of your replacement windows. Keep up with annual inspections and regularly follow some simple tasks to keep your windows in tip-top shape.

  • Cleaning Your Windows
    You can do a lot for your windows with a simple wash. Your windows can be significantly impacted by weather, and if grime builds up on your glass panes, it’s harder to spot issues like cracks and film problems. With clean windows, you’ll know exactly when problems come up, so you can deal with small issues before they become huge (and costly!) problems. Need an added bonus? Your house will sparkle—pristine windows are sure to amp up your curb appeal.

  • Film and Coating Maintenance
    If your windows have coatings and film, you’ll need to inspect them regularly. Be sure to watch for cracks or rips in window coatings and have them repaired or replaced as quickly as possible.

  • Examine Caulking and Sealant
    Regularly take a look at the caulking and sealant along your windows’ frames. If you spot any crevices, cracks, or holes, be sure to seal them as quickly as possible. Even tiny openings in your window’s frame can reduce your home’s energy efficiency and let in moisture, which can cause mildew, mold, and rot.

  • Maintain Your Frames
    Different frames need different types of maintenance. Usually, wooden frames take more effort, especially if you live in a rainy area or near the coast. If you have wooden frames, watch closely for moisture damage; if you don’t catch it in time, your frame can mold, rot, and displace your windowpane.

Other framing options, including aluminum, vinyl, and fiberglass, are much easier to maintain. Taking just a few minutes a week to wipe down these windows can make them last much longer, and all you need is some gentle soap, warm water, and a sponge—and of course a little bit of elbow grease.

Give your home a facelift with new windows and reap the rewards of energy savings and increased security. Making the right choice in high efficiency windows can keep your family safe and happy, so get started today.